RosettaCodeData/Task/Primality-by-trial-division/Common-Lisp/primality-by-trial-division-1.lisp
2018-06-22 20:57:24 +00:00

6 lines
152 B
Common Lisp

(defun primep (n)
"Is N prime?"
(and (> n 1)
(or (= n 2) (oddp n))
(loop for i from 3 to (isqrt n) by 2
never (zerop (rem n i)))))